There has been known a conventional air-flushing device for cleaning a cleaning object by blowing the air to the cleaning object. For example, Patent Literature 1 discloses an air-flushing device for air-flushing a cleaning object by causing a nozzle to blow clean air that is supplied from a clean air supply section, the air-flushing device including, in an air flow path between the clean air supply section and the nozzle, a valve which is made of an abrasion-resistant resin and opens and closes the air flow path.
The air-flushing device disclosed in Patent Literature 1 is able to open and close the valve with high frequency, thereby carrying out pulse blowing. For example, the valve is opened and closed 3 times to 10 times per second. This allows the inside of the valve to have an injection pressure indicated by a line graph of a serrated form having a vertex indicative of a maximum pressure P1. Thus, the air-flushing device carries out air-flushing with use of the maximum pressure P1 as a working pressure. As has been described, the conventional air-flushing device controls by time the frequency of opening and closing the valve.